The invention relates to a hip joint socket for insertion into bone tissue.
Hip joint endoprostheses consist of a hip joint socket which is anchored in the pelvic bone and a ball, which is inserted into the socket for rotation therein, and is anchored to a shaft in the femur.
Hip joint sockets consist of an outer metal shell which constitutes the external shape of the implant, and an inner antifriction liner which is made of ceramic or of plastic such as an ultra-high molecular weight polyethylene (UHMWPE).
It is state of the art to fix the antifriction liner in the metal shell by means of a taper lock having an angle of about 5.degree. 43', i.e., an angle ratio of 1:10. A disadvantage of this socket is that the antifriction liner easily becomes canted when inserted into the metal shell resulting in an unequal distribution of forces which, under some circumstances, can result in a fracture of the internal antifriction liner especially if it is made of ceramic. Another important disadvantage is that after the antifriction liner or socket has been installed, the antifriction liner can no longer be removed nondestructively due to the high seizing forces. However removeability without destruction is extremely important for the surgeon. A further disadvantage is that due to the configuration of the antifriction liner and socket insert the overall size of the implant has to be made relatively large. This is a disadvantage from the medical viewpoint because either it entails significant bone loss or, if the bone wall is thin, may prevent installation of such an implant.